Fluid heat exchange apparatus



Feb. 18, 1941.

T. C. TOOMEY ETA!- FLUID X'IEAT EXCHANGE APPARATUS Filed Aug. 27, 1937 4Shouts-Shoot 1 INVENTORS Thomas C Toomey Arthur EPaynor I ATTORNEY.

Feb. 18, 1941.

FLUIDHEAT EXCHANGE AIPARATUS 'r. c. TOOMEY er 2,231,970

Filed Aug. 27,. 19s? 4 Sheath-Shoot 2 v INVENTORS Thomas C. Toomey 2;RArthur E. Raynor ATTORNEY.

Feb. 18, 1941. A v QTQQMEY 575k 2,231,970

FLUID HEAT EXCHANGE, APPARATUS Filed Aug. 27, 1937 4 Shoots-Sheet 3 VmvmoRs Thomas C Toomey Q E. Raynor I 1941- 'r. c. TOOMEY Ema. 2,231,970

FLUID HEAT EXCHANGE APPARATUS Filed Aug. 27, 1937 4 sums-shat 4 YINVENTORS Thomas C Romey BY flrzhur E. Raynor ATTORNEY.

Patented Feb. 18, 1941 UNITED STATES PATENT OFFICE 2,231,970 r FLUIDHEAT EXCHANGE APPARATUS Jersey Application August 27, 1937, SerialN0./161,174

A 6 Claims. (01. 122-235) This invention relates to fluid heat exchangeapparatus in which fuel burning conditions and heat exchange conditionsare so co-ordinated that the apparatus is capable of high rates of heatliberation and high rates of heat absorption at large temperaturedifferentials between the heat transmitting combustion products and theheat absorbing elements.

It is an object of the invention to economically produce high pressureand high temperature.

steam for the ultimate production of power. The two stage radiant boilerfor producing the steam is characterized by its ability to burn variousfuels in suspension while emciently absorbing 15 heat from the productsof combustion and effecting the separation of non-combustible residuesof the fuels to such a degree that continuity of operation of theapparatus and the thermal efficiency thereof are maintained overeconomically advantageous long time periods.

The invention presents a radiant boiler in which the combustion of thefuel. and the heat absorption by the working fluid is developed instages, each stage involving such co-ordination of furnace conditionsand heat absorbing surfaces that the ultimate desideratum of slag freefurnace gases at the proper temperature at the furnace outlet will beattained. In the operation of the boiler, combustion of the fuel iseffected 39 in a high temperature stage wherein, when pulverized coal isused as a fuel, the ash constituents of the coal are fused and caused tocoalesce. These constituents simultaneouslytransfer heat to fluid cooledfurnace walls. In the second stage, the 35 products of combustion aresubjected to a temperature reduction by the radiant transfer of theirheat to wall surfaces of high absorptivity. In this stage not only thegaseous products of combustion, but also the "non-gaseous or molten toresidues are subject to a rapid and considerable reduction intemperature. This action brings the gases within the allowabletemperature limits for contact thereby with subsequent superheatingsurfaces and the molten residues are chilled 4i and congealed to such adegree that deleterious deposits of these residues upon superheatersurfaces is eliminated, and discharge of the separated residues from thefurnace is facilitated.

It is an object of the invention to maintain such 50 high furnacetemperatures in the primary furnace stage that rapid and completecombustion of the fuel is eflected. In this stage the ash releasedduring combustion of such an ash-bearing fuel as pulverized coal ismaintained in a molten ooh- I 55 dition as slag in order that it may becontinuously or intermittently removed from the furnace while still in amolten condition.

In the secondary furnace stage the object is to present .furnace coolingelements of higher rates of heat absorptivity to rapidly receive theradiant heat from the gases and any non-gaseous particles that may be insuspension in the gases, and to so reduce their temperatures,particularly that of the non-gaseous particles in suspension, that whenthey contact with the convection heating surface beyond the secondaryfurnace stage, they will be at a temperature below their fusiontemperature and will, therefore, be in a dry or such a non-stickycondition that the accumulations of molten slag upon the elementsproviding the convection heating surface will not occur.

Other objects of the invention will appear in the following descriptionwhich refers to the accompanying drawings, 'in which:

Fig. 1 is a vertical section through an illustrative embodiment of theinvention.

Fig. 2 is a view in the nature of a vertical sec- I tion taken at aplane at right angles to the plane of the Fig. 1 section, approximatelyon the line 2-2 of Fig. 1.

Fig. 3 is a detail view on an enlarged scale showing, in verticalsection, the arrangement of the submerged boiler drum with respect tothe adjacent water wall header.

Fig. 4 is a vertical section showing in detail the arrangement of thevertically inclined slag screen tubes with reference to the adjacentwater Wall of the secondary stage of the furnace.

Fig. 5 is a detail view in horizontal section showing the type ofrefractory faced furnace wall employed in the primary or hightemperature furnace stage.

Fig.6 is a horizontal section on the line Elfi of Fig. 1, showing thearrangement of tubes at the upper part of the second stage.

Fig. 7 is a detail view taken on the sectional line l-l' of Fig. 1,showing the construction of the second stage.

Fig. 8 is a detail view showing the manner in which the coils of theconvection section are mounted.

In Fig. 1 of the drawings the primary furnace stage is indicated at l tand the secondary furnace stage generally indicated at l2. In theprimary furnace stage high rates of combustion and high temperaturesprevail. The walls of this furnace are defined by fluid cooled tubeswhich are connected into the boiler circulation. Such tubes (see tubesi4 and [6 of Fig. 5 of the drawings) are covered on their furnace sidesby ceramictt "refractory material I 8 which is anchored to the tubes andthermally maintained by the cooling action of the fluid within the tubesby metallic extensions 2U distributed over the furnace faces of thetubes. These extensions are preferably welded to the tubes. The ceramicmaterial is thus bonded to the tubes so that it is maintained thereon asan integral part of the walls even though the furnace face layel s ofthe walls are maintained continuously at high temperatures during theoperation of the apparatus.

The walls of the secondary furnace stage I 2 present heat absorbingsurfaces of high rates of heat absorptivity. These walls may be in theform of a tube to tube arrangement of steam generating wall tubesdefining the stage boundaries' and having their furnace face surfacesbare, or in the form of a partial stud tube arrangement in which thewalltubes are spaced apart and the spaces between the adjacent tubes ofthe wall in the plane of the boundary closed against passage of gases byceramic refractory material maintained on the tubes and bonded theretoby studs or extensions secured to the tube and projecting therefrom intothe inter-tube spaces. Alternatively, the inter-tube spaces in thesecondary furnace stage may be closed by 'imperfo- I rate metalextensions projecting from the tubes and arranged in the planes of theboundaries of this stage with the furnace faces of the tubes bare andexposed to the furnace gases. Fig. 1 of the drawings indicates a wallstructure in which the tubes of the secondary furnace stage l2 havemetallic blocks 22 held in contact with the tubes and forming agas-tight wall. These blocks not only present heat absorbing surfaces ofhigh rates of heat absorptivity, but they facilitate the removal of ashor molten slag that might be deposited on the walls. They effect thisresult by providing natural cleavage planes along their smooth wallfaces, these planes marking'sharp delineatlons between the furnace facesand any slight slag accumulations which may occur. This results in theslag naturally breaking away from the wall after it has accumulated tosuch a degree that its weight is greaterthan that which can normally besustained by the relatively low adhesion resulting from the smoothnatural cleavage planes provided by the surface of the wall.

' High rates of combustion prevail in the primary furnace stage and highfurnace gas temperatures well above the fusion temperatures of the ashcontent of pulverized coalare maintained. Burners 30, 32, and 34 aresupplied with air preheated to a high temperature and the furnace parts,including the burners, are so arranged that a high degree of turbulenceresults in a thorough mixing of the preheated air and fuel, whichcondition is desirable for the rapid and complete combustion of thefuel. These burners are preferably of a type known as com- I This termconnotes burners and allowed to flowfrom the furnace through the slagtap opening 38; In the particular embodiment of the inventionillustrated in Fig. 1 of the drawings, the burners are arranged so as tofacilitate the flow of this slag toward this slag tap opening.

The molten ash or slag particles in the primary furnace stage II) areinitially in suspension in the furnace gases and not all of theseparticles are deposited upon the furnace floor. Some of them pass withthe gases into the secondary furnace stage l2. The outlet openings 40through which this movement of the gases takes place are indicated inFig. 2 of the drawings and they are defined by the refractory covereddivision wall tubes 42 which connect the upper header 44 with the lowerheaders 46. Above the outlets '40 these tubes, with their refractorycoverings constitute an imperforate division wall which acts as a baflleto deflect the gases downwardly.

As the gases with their suspended slag particles move through the secondstage, heat is radiated from these particles and from the gases to thefluid cooled heat absorbing surfaces provided by the wall tubes and themetallic furnace wall blocks. This heat transfer results in suchdecreases in the temperature of the gases and the non-gaseous particlesin suspension that the particles are in a dry solid form before theycontact with the heating surfaces of tubes beyond the second stage. Thisdesirable action is enhanced by action resulting from the differencebetween solid and gaseous radiation. The greater radiation from thesolid particles results in these particles attaining a somewhat lowertemperature than the surrounding gases. Thus fouling of the spaced tubesof convection heating surfaces beyond the second stage, and particularlythe tubes of the superheater 49 is prevented.

The furnace gases and their suspended nongaseous particles beyond thesecond stage are further cooled by contact with and the radiant transferof heat to the widely spaced slag screen tubes 50-54, inclusive. Thesetubes areconnectedinto the boiler circulation by reason of theircommunication at their lower ends with the submerged drum 55 and attheir upper ends with the front drum 58. During the operation of theapparatus a mixture of steam and water flows up wardly through thesetubes to the drum 58, other boiler circulation taking place through thecirculators 60-63, inclusive, the steam and water drum 88, the steamcirculators 69-and 10, and the water circulators T2.

The tubes 54 are preferably in wall alignment and the spacesbetweenthese tubes are closed by refractory material which forms thebaffle 14 extending upwardly from the drum 55 to a position near the topof the secondary stage side wall 76. The furnace gases pass around thetop of this bafile as indicated by the arrow 18, move downwardly throughthe gas pass 80 and pass between the screens formed by the lower partsof the circulators BI, 62, and 83 to the spaced tubes of the superheater49.] All of these tubes contacting with the furnace gases leaving thesecond stage are widely spaced so that they do not excessively cool thefurnace gases before they reach the superheater. When high superheat ispiovided the high temperature gases thus contacting with the superheaterelements eliminate the necessity of providing an excessive amount ofsuperheating surface to attain the superheat de- .SiIEd.

The superheater 49 consists of the closely spaced tube sections ofreturn ben'd coils extending across the upward flow of gases in the gas.pass 90 and receiving saturated steam from an inlet header 92 connectedby the tubes 94 with thesteam space of the drum 68. The superheaterpreferably operates upon the countert flow principle with the steamflowing downwardly to'the superheater outlet header 90 while the gasesflow upwardly in the gas pass 90 across the tube sections of theeconomizer 08 and to the flue I00.

The tube sections of the superheater coils and the economizer coils maybe maintained in their properly spaced arrangement by supports welded tothe upright sections of the circulators 60-63,

inclusive, such supports permitting the coils to be readily removed andreplaced. Furthermore, the cooling action of the fluid in thecirculators upon the metallic supports prevents damage to the supportsby the high temperature furnace gases. I

lhe gas pass 90 for the superheater is defined on one side by the wallI02 and upon the opposite side by a partition I00 which separates thebypass IOB from the gas pass. 90. Feed water entwo economizer sectionsthrough the bypass I06 is regulated by the bypass dampers II8 which incombination with the dampers I20 at the outlet of the gas pass 90 serveto maintain uniform steam temperatures over a wide range of gas flow.

The front wall and roof of l the combustion chamber I0 of the primaryfurnace stage are defined by the tubes I3 which extend upwardly past theburners 30 and 32 and connect at their.

upper ends to the' header 44. These tubes are covered on their furnacesides with ceramic refractory material as indicated in Fig. 5. Similararrangements of tubes and refractory coverings constitute the side wallsof" the primary. stage and the floor is defined by the tubes I22communicating at their forward ends with the header I24, and" at theirlower ends with the header I26 which maybe suitably connected into theboiler circulation. The side walls may be sustained by bottom supportssuch as are shown beneath the header I24.

The wall tubes I28, connecting the headers 44 and I30 act as risers toconduct the mixture of steam and water from the wall tubes of thecombustion chamber I0 upwardly and this mixture passes directly from theheader E30 through suitable uptake connections to the steam and waterdrum 60.

The submerged drum 55.15 1 preferably supported by the tubes 50-54inclusive, and the tubes 63, and it is thus susceptiblev of somedownward and lateral movement when the boiler is brought up to operativetemperatures. The header I30 is not supported by the same arrangement oftubes and hence is not subjectedto the same movements. Therefore, a gasseal is provided between the header, I30 and the drum 55. This seal isshown in "detail in Fig. 3 of the drawings. It consists :of refractoryblocks I40 held in position vertically with respect to the drum by aplate I42 and lugs I40. The plate is preferably welded to the drum 55 asshown and the lugs I44. are secured to an upright plate at their upperendswith the headers 254.

I46, which, in turn, is welded to the drum. The blocks, I40 are freelymovable horizontally in the guideway provided between the plate I42 andthe lugs I44 and this guideway maintains the blocks I40 in sealingrelationship to the drum 55. An intersecting vertical guideway for theblocks I40 is provided between the upright plate I48 and the lugs I50,the latter being interspersed relative to the lugs I44.

The plate I48 is preferably welded to the header I30 and the lugs I50are fixed to this header through the intermediacy of the horizontallyextending plate I54; Spaced from the lower flange of-the Z-bar I52 andrigidly securedthereto is a guide plate I55 which co-operates with thelower flange to provide a horizontal guideway for the horizontal flangeof the floating angle I58. The vertical flange of thisangle is free toslide in a guideway formed by the depending plate I and its companionplate-I62. The latter elements are rigid with respect to the drum $5.The spaces below and laterally of the sealing blocks I40 and above thefloating angle 558 may be filled with some suitable insulating materialsuch as asbestos.

The tubes 50 and SI are widely spaced at positions wherein they aretraversed by the furnace gases, but at positions near the wall tubes I10these tubes are brought into a single upright wall alignment. From thesepositions upwardly the furnace wall is completed by ceramic refractorymaterial I12 closing the spaces between the upper parts of the tubes 50and 5| and anchored and thermally bonded to the tubes by metallic studsI14. This partial stud tube"-wall I8! is suspended from the beam I80 ofthe boiler setting framework by the hangers I02. The roof shown as anupward continuation of the wall I8I is also supported by the hangersI82.

Provision is made for permitting relative movement'between the boilerwall IM and the second stage furnace wall defined by the wall tubes I10.The latter tubes, as indicated in Fig. 4 of the drawings, are curvedoutwardly at their upper ends and are connected to the header I90. Atthe positions wherein these tubes curve away from their verticalpositions the spaces between the tubes are closed by metallic blocks edby the spaced plates 200 and 202 which are fixed with reference to thetubes 50 and SI by the angle 200, the plate 200, and the studs 208.Sealing blocks 2? of refractory material are held against the'partialstud tube boiler wall by brackets 2I2 which co-operate with that wall toform a vertical guideway for the blocks. The lower surfaces of theseblocks are held in contact with the upper surfaces of the blocks I92 bythe brackets 220 which are fixed with reference to the other guidemembers I94 and I96.

A horizontal guideway for the blocks 2I0 is thus formed and the spacesbetween these blocks and the other seal forming elements may be filledby a compressible heat insulating material.

The. side walls 18 of the second furnace stage include the upright w-alltubes 250 communicating at their lower ends with the headers 252 and Thelatter are connected with the steam space of the drum 68 by risers .255.The parts of these. tubes above the level'of the gas outlets 40 havetheir spaces closed by the metallic wall blocks 22 but in the highertemperature turning zone of the furnace gases adjacent the outlets thewalls of the second stage are preferably provided with a stud .tube andceramic refractory construction. The downwardly inclined lower parts ofthe wall tubes I10 are provided with a, protective tube covering. Thesetubes communicate attheir lower ends with a header 260 which may beconnected with the upper header I90 by the recirculators 262-.Appropriate risers 2 connect the upper header I90 with the steam andwater space of the drum 68.

The division wall 42, between the primary stage II) and secondary stagel2 consists of spaced;

tubes with a full stud tube construction over their higher temperaturesides presented toward the primary stage. high temperature ceramicrefractory furnace face to the combustion chamber ill of the first stageand is similar to the construction for the'remaining walls of thiscombustion chamber. The ceramic refractory material constituting thelining for this chamber is installed over the studs and the tubes in amoldablecondition and is tamped stud tube construction. The upperportions of these tubes are preferably in single row alignment, but justabove the gas outlets 40 these tubes are bent out of this wall alignmentand below these points the tubes are arranged to define the side wallsof the outlets 40. The lower parts of these tubes are preferablyprovided with the full stud tube construction. These parts, constitutingthe walls of the gas outlets 40 act as a slag screen, causing gas mixingto promote combustion of any combustibles that may-remain unburned inthe gases at this point, and furthermore effecting some separation ofslag particles by adhesion thereto.

The wall tubes I70 forming the rear wall of the second stage l2 are heldin wall alignment by guides which include the beams 210. These beams maybe fixed .to the columns 212 and have a slidable relation to the walltubes I10 in order that the latter may be held in wall forming alignmentwhile still free to move because of expansion or contraction. It is alsoclearly indi-' cated in Fig. '1 of the drawings that the rear wall ofthe second furnace stage I2 is inclined downwardly toward the floor 36of the primary furnace stage I 0, and means are shown for supportingthis lower part of the wall in this position.

The illustrative embodiment of the invention indicated in the drawingsinvolves an arrangement of the diiferent stages and the other componentswhereby economical power generation may be effected over a wide range ofgas flow. This results from the high rates of combustion and highfurnace temperatures which may be attained in the primary furnace stage.Considering the range of operation there is always some range belowwhich it is diflicult to maintain the slag at the bottom of the furnacein a molten condition so that it may be effectively removed, and thehigher the temperature of the primary stage at a normal or maximumcapacity the higher the temperature will be at lower capaci- Thisconstruction presents a I of combustion and high temperatures prevail.

This promotes long continued effectiveness of the convection surfaceswhen the operation of the unit is considered from the standpoint of slagaccumulations on such surfaces, and additionally, further acceleratesthe rapid decrease in temperature of the gases in the secondary stage.

- The above indicated arrangement of the elements wherein the economizerand the super- ,heater are positioned laterally of the top of thesecondary stage and above the high temperature primary stage alsoinvolves an effective utilization of head room and the total availablespace for the whole installation. This arrangement also involves aneconomy of cost as to the supporting framework of the boiler setting.Some of the parts of the setting framework utilized in conjunction withthe-erection and support of the primary stage may also be utilized inconnection with the erection and support 'of the economizer andsuperheater. These advantages would not be present if the convectionsection consisting of the economizer and superheater were locatedoppositely of the second stage, with respect to the primary stage.

Although the invention has been described with reference to theparticular embodiments which are shown in the accompanying drawings, itis to be appreciated that it is not limited to all of the details andarrangements of elements shown in those drawings. Various components ofthe steam genera-ting unit illustrated in Fig. 1 of the drawings may beutilized in combinations of the other components which may vary fromthose illustrated, within the scope of the sub-joined claims.

We claim:

1. In a steam boiler of the bent .tube type, an upper drum, a lowerdrum, steam generating tubes connecting said drums and having vertical-1y inclined parts extending across the path of furnace gases, the upperparts of said tubes being bent to extend upwardly in wall formingalignment,- refractory means closing the spaces between said upper partsto form an upright boiler setting wall, means completing the boilercirculation through said drums and tubes, a furnace including a waterwall adjacent the lower portion of said setting wall and substantiallyparallel thereto, and a combined expansion joint and gas seal structurebetween said walls, for maintaining a gas tight closure while permittingrelative movements of said walls due to exposure to a wide range offurnace gas temperatures and due to the provision of separate supportsfor the walls.

2: In a vapor generator, inclined vapor generating tubes having partsextending across the path of furnace gases, the upper parts of the tubesdefining a gas confining wall, refractory means associated with saidupper parts to close the spaces between the tubes, a second wallextending downwardly from the first wall and including spaced wallcooling tubes, refractory means closing the spaces between the lattertubes, means chamber, a lower fluid chamber, steam generat-- ing slagscreen tubes connecting said chambers and having vertically inclinedparts extending in widely spaced relationship across the path of furnacegases, the upper parts of said tubes being bent to extend upwardly inwall forming align-, ment, refractory means closing the spaces betweensaid upper parts to form an upright boiler setting wall, meanscompleting the boiler circulation through said fluid chambers and tubes,a furnace including a water wall adjacent the low er portion of saidsetting wall and substantially parallel thereto, and a combinedexpansion joint and gas seal structure between said walls formaintaining a gas tight closure while permitting irelative movements ofsaid walls due to exposure to a wide range of furnace gas temperaturesand due to the provision of separate supports for the walls.

4. In a steam boiler, means forming a lower water chamber, means'formingan upper water chamber, inclined steam generating tubes directlyconnecting said chambers, spaced furnace wall tubes arranged as a partof a furnace wall with c its upper end adjacent the lower water chamber,

sealing means permitting relative movements of said wall and the lowerchamber while preventing the escape of furnace gases therebetween, saidmeans including a floating angle. a similar furnace wall adjacent theupper ends of some of said steam generating tubes, similar vsealingmeans between the latter tubes and the lastnamed furnace wall, and meansfor burning fuel in the furnace.

5. In a water tube steam boiler, an upper fluid chamber, a lower fluidchamber, steam generating slag screen tubes connecting said chambers andhaving inclined parts extending in widely spaced relationship across thepath'of furnace gases, other parts of said tubes being bent to ex- ,tendupwardly in wall defining alignment, means co-operating with said otherparts to form an upright boiler setting wall, means completing theboiler circulation through said fluid chambers and tubes, a furnaceincluding a water wall adjacent the lower portion of said setting walland substantially parallel thereto, and a combined expansion joint andgas seal structure between said walls for maintaining a gas-tightclosure while permitting relative movements of said walls due toexposure to a wide range of furnace gas temperatures and due to theprovision of separate supports for the walls.

6. In fluidheat exchange apparatus including a furnace; two adjacentfluid cooled structures exposed to the heat of furnace gases; separatesup orts for said structures; and a gas tight triple seal between saidstructures; said seal including an inner component including arefractory member, means maintaining the refractory member in contiguousrelationship to each of said structures, an outer component including abody movable with respect to at least one of said structures, and looseheat insulation material between said body and said refractory member,said inner and outer components being maintained in their operativepositions independently of said insulation material.

THOMAS C. TOOMEY. BAYNOR,

III

